Microbe control in food processing and related industries

ABSTRACT

A PROCESS FOR ELIMINATING OR SUBSTANTIALLY REDUCING THE PRESENCE OF BACTERIA IN SUBSTANTIALLY BACTERIA-FREE ZONES SERVED BY AT LEAST ONE CONVEYOR. THIS PROCESS COMPRISES APPLYING A LUBRICANT TO SUCH CONVEYOR WHICH CONSISTS ESSENTIALLY OF CONCENTRATE AND WATER IN A PROPORTION OF CONCENTRATE TO WATER OF ABOUT 1:50 TO 1:500 AND WHEREIN SAID CONCENTRATE CONSISTS ESSENTIALLY OF BY WEIGHT FROM ABOUT 20 TO 80 PERCENT WATER, ABOUT 0 TO 15 PERCENT SEQUESTERING AGENT, ABOUT 0 TO 30 PERCENT ANIONIC SURFACE ACTIVE AGENT, ABOUT 2 TO 40 PERCENT FATTY ACID SOAP, ABOUT 0 TO 40 PERCENT PROPYLENE GLYCOL, ABOUT 0 TO 15 PERCENT NINIONIC SURFACE ACTIVE AGENT, AND AT LEAST ABOUT 0.5 PERCENT COMPOUND SELECTED FROM THE GROUP CONSISTING OF BISPHENOLS, THIADIAZINE THIONE, DITHIOCARBAMATE, AND MIXTURES THEREOF.

United States Patent MICROBE CONTROL IN FOOD PROCESSING AND RELATED INDUSTRIES Donald F. Garvin, Berkley, and Otto T. Aepll, Southgate, Mich., assignors to BASF Wyandotte Corporation, Wa e Mich.

No Drav iiig. Filed July 18, 1968, Ser. No. 745,690 Int. Cl. Cm 1/32, 1/38 US. Cl. 25234.7 4 Claims ABSTRACT OF THE DISCLOSURE A process for eliminating or substantially reducing the presence of bacteria in substantially bacteria-free zones served by at least one conveyor. This process comprises applying a lubricant to such conveyor which consists essentially of concentrate and water in a proportion of concentrate to water of about 1:50 to 1:500 and wherein said concentrate consists essentially of by weight from about 20 to 80 percent water, about 0 to percent sequestering agent, about 0 to 30 percent anionic surface active agent, about 2 to 40 percent fatty acid soap, about 0 to 40 percent propylene glycol, about 0 to 15 percent noniomc surface active agent, and at least about 0.5 percent compound selected from the group consisting of bisphenols, thiadiazine thione, dithiocarbamate, and mixtures thereof.

In breweries, wineries, pharmaceutical, and food processing plants, for many products it is often necessary to conduct some operations in an organism-free room such as a clean room for filling bottles 'with filtered and/or sterilized liquid. In such food plants, often it is possible for bacteria to get into such clean rooms or zones through various sources such as conveyors or water contaminated with bacteria from a storage tank which would disseminate bacteria into critical areas or zones.

Accordingly, it is a purpose of the instant invention to provide a method or process for eliminating or substantially reducing the presence of organisms, such as bacteria, yeast, and mold, that might be present or enter into a clean room or zone, particularly where bottles or other materials are conveyed in the room by conventional conveyor apparatus.

In acordance with the instant invention, a process is provided for eliminating or substantially reducing the presence of bacteria in substantially bacteria-free zones served by at least one chain-type or other conveyor. This process comprises applying a lubricant to such conveyor which lubricant consists essentially of concentrate and water which concentrate, in turn, consists essentially of by weight from about to 80 percent water, about 0 to 15 percent sequestering agent, about 0 to 30 percent anionic surface active agent, about 2 to 40 percent fatty acid soap, about 0 to 40 percent propylene glycol, about 0 to 15 percent nonionic surface active agent, and at least about 0.5 percent compound selected from the group consisting of bisphenols, thiadiazine thione, dithiocarbamate, and mixtures thereof.

In accordance with a preferred embodiment of the in stant invention, the concentrate consists essentially of by weight about 30 to 70 percent water, about 2 to 8 percent sequestering agent, about 2 to 10 percent anionic surface active agent, about 4 to 20 percent fatty acid soap, about 0 to 20 percent propylene glycol, about 2 to 10 percent nonionic surface active agent, and about 1 to 5 percent of 3,583,914 Patented June 8, 1971 ice a composition selected from the group consisting of bisphenols, thiadiazine thione, dithiocarbamate, and mixtures thereof.

For convenience and economy in transporting and storing such lubricant, it is preferred to employ a concentrate, as described above, which is then diluted with water in proportions by volume of from about 1:50 parts concentrate to water to 1:500 parts concentrate to water.

If lubricants are to be stored or shipped in unlined drums or tanks, the inclusion of a chelating agent for iron will prevent discoloration of compositions containing bisphenols due to the formation of iron phenolate.

It is preferred to employ as the sequestering agent salts of ethylene diamine tetraacetic acid and nitriloacetic acid. These sequestering agents may be added to the composition in the form of the salts or the acid may be added along with a sufficient amount of metallic hydroxide or alkanolamine to neutralize the acid.

Any sequestering agent which will complex calcium and magnesium ions from water may be employed in this invention. Additional suitable sequestering agents are trans- 1,2-diaminocyclohexane tetraacetic acid monohydrate, diethylene triamine pentaacetic acid, pentasodium salt of N-hydroxyethylene diamine triacetic acid, trisodium salt of N,N-di(beta-hydroxyethyl) glycine, and sodium salt of sodium glucoheptonate.

Where the formula is diluted in tap water, conventional metallic soap dispersants may be necessary or desirable in addition to the sequestering agents.

Anionic surface active agents which may be employed include linear alkyl benzene sulfonic acids, alpha-olefin sulfonates, alkyl diphenyl oxide disulfonates, sodium N- methyl-N-alkyl-taurate, alkyl sulfonated amides, di(2- ethylhexyl) sulfosuccinate, dioctyl sodium sulfosuccinate, sodium sulfonate of oleic acid, anionic phosphate esters, alkyl ether sulfates, alkyl polyethyleneoxy esters, alcohol sulfates such as sodium lauryl sulfate, the product of chlorosulfonation of parafiin hydrocarbons, e.g., octadecenyl sulfonate and the condensate of a fatty acid chloride with an amine.

For the sake of simplicity in formulating the composition, instead of adding fatty acid soap as such it is preferred to simply add fatty acid in amount from about 2 to 30 weight percent for the broad composition or 4 to 15 percent by weight in the preferred composition and then add a sufiicient amount of a metal hydroxide or an alkanolamine to neutralize the fatty acid to produce the fatty acid soap. Where the sequestering agent is also added in the acid form, the metal hydroxide or alkanolamine is added in sufficient amount to neutralize both the sequestering agent acid and the fatty acid. Preferred fatty acids for this purpose are tall oil fatty acids with low rosin content of about 0.5 to 0.9 percent by weight and which generally comprise approximately 52 percent by weight oleic acid, 45 percent by weight linoleic acid, 1 percent by weight linolenic acid, and 2.3 percent by weight saturated acid. Coconut oil fatty acids generally comprised of 50 percent lauric, 20 percent myristic, 10 percent oleic, 10 percent palmitic, 8 percent of other saturated fatty acids, and about 2 percent unsaturated fatty acids are also desirable for this purpose. Additional useful fatty acids include those derived from tallow, soya beans, corn, cottonseed, palm, and. blends or hydrogenated forms of the basic type of fatty acid to give desired characteristics such as low solubilization temperature, viscosity, and reduced corrosion tendency.

Sodium or potassium hydroxide and mono-, di-, and triethanolamine or isopropylamine are the preferred source used for neutralizing and converting fatty acids and sulfonic acid derivatives to soap or amides. Potassium hydroxide and monoethanolamine are preferred for their ability to produce compounds with a pH and foam generating capacity suitable for conveyor lubricants.

The nonionic surface active agents which are advantageously employed in the compositions of the invention are generally the polyoxyalkylene adducts of hydrophobic bases wherein the oxygen/ carbon atom ratio in the oxyalkylene portion of the molecule is greater than 0.40. Those compositions which are condensed with hydrophobic bases to provide a polyoxyalkylene portion having an oxygen/carbon atom ratio greater than 0.40 include ethylene oxide, butadiene dioxide and glycidol, mixtures of these alkylene oxides with each other and with minor amounts of propylene oxide, butylene oxide, amylene oxide, styrene oxide, and other higher molecular weight alkylene oxides. Ethylene oxide, for example, is condensed with the hydrophobic base in an amount sufficient to impart water dispersibility or solubility and surface active properties to the molecule being prepared. The exact amount of ethylene oxide condensed with the hydrophobic base will depend upon the chemical characteristics of the base employed and is readily apparent to those of ordinary skill in the art relating to the synthesis of oxyalkylene surfactant condensates.

Typical hydrophobic bases which can be condensed with ethylene oxide in order to prepare nonionic surface active agents include monoand polyalkyl phenols, polyoxypropylene condensed with a base having from about 1 to 6 carbon atoms and at least one reactive hydrogen atom, fatty acids, fatty amines, fatty amides and fatty alcohols. The hydrocarbon ethers such as the benzyl or lower alkyl ether of the polyoxyethylene surfactant condensates are also advantageously employed in the compositions of the invention.

Among the suitable nonionic surface active agents are the polyoxyethylene condensates of alkyl phenols having from about 6 to 20 carbon atoms in the alkyl portion and from about 5 to 30 ethenoxy groups in the polyoxyethylene radical. The alkyl substituent on the aromatic nucleus may be octyl, diamyl, n-dodecyl, polymerized propylene such as propylene tetramer and trimer, isooctyl, nonyl, etc. The benzyl ethers of the polyoxyethylene condensates of monoalkyl phenols impart good properties to the compositions of the invention and a typical product corresponds to the formula:

Higher polyalkyl oxyethylated phenols corresponding to the formula:

O (CHzCHzO)nH 1 wherein R is hydrogen or an alkyl radical having from about 1 to 12 carbon atoms, R and R are alkyl radicals having from about 6 to 16 carbon atoms and n has a value from about 10 to 40, are also suitable as nonionic surface active agents. A typical oxyethylated polyalkyl phenol is dinonyl phenol condensed with 14 moles of ethylene oxide.

Other suitable nonionic surface active agents are cogeneric mixtures of conjugated polyoxyalkylene compounds containing in their structure at least one hydrophobic oxyalkylene chain in which the oxygen/carbon atom ratio does not exceed 0.40 and at least one hydrophilic oxyalkylene chain in which the oxygen/carbon atom ratio is greater than 0.40.

Polymers of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide, styrene oxide, mixtures of such oxyalkylene groups with each other and with minor amounts of polyoxyalkylene groups obtained from ethylene oxide, butadiene dioxide, and glycidol are illustrative of hydrophobic oxyalkylene chains having an oxygen/carbon atom ratio not exceeding 0.40. Polymers of oxyalkylene groups obtained from ethylene oxide, butadiene dioxide, glycidol, mixtures of such oxyalkylene groups with each other and with minor amounts of oxyalkylene groups obtained from propylene oxide, butylene oxide, amylene oxide and styrene oxide are illustrative of hydrophilic oxyalkylene chains having an oxygen/carbon atom ratio greater than 0.40.

Further suitable nonionic surface active agents are the polyoxyethylene esters of higher fatty acids having from about 8 to 22 carbon atoms in the acyl group and from about 8 to 30 ethenoxy units in the oxyethylene portion. Typical products are the polyoxyethylene adducts of tall oil, rosin acids, lauric, stearic and olei-c acids and the like. Additional nonionic surface active agents are the polyoxyethylene condensates of higher fatty acid amines and amides having from about 8 to 22 carbon atoms in the fatty alkyl or acyl group and about 10 to 30 ethenoxy units in the oxyethylene portion. Illustrative products are coconut oil fatty acid amines and amides condensed with about 10 to 30 moles of ethylene oxide.

Other suitable polyoxyalkylene nonionic surface active agents are the alkylene oxide adducts of higher aliphatic alcohols and thioalcohols having from about 8 to 22 carbon atoms in the aliphatic portion and about 3 to 50 oxyalkylene units in the oxyalkylene portion. Typical products are synthetic fatty alcohols, such as n-decyl, nundecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl and mixtures thereof condensed with 3 to 50 moles of ethylene oxide, a mixture of normal fatty alcohols condensed with 8 to 20 moles of ethylene oxide and capped with benzyl halide or an alkyl halide, a mixture of normal fatty alcohols condensed with 10 to 30 moles of a mixture of ethylene and propylene oxides, a mixture of several fatty alcohols condensed sequentially with 2 to 20 moles of ethylene oxide and 3 to 10 moles of propylene oxide, in either order; or a mixture of normal fatty alcohols condensed with a mixture of propylene and ethylene oxides, in which the oxygen/carbon atom ratio is less than 0.40, followed by a mixture of propylene and ethylene oxides in which the oxygen/carbon atom ratio is greater than 0.40, or a linear secondary alcohol condensed with 3 to 30 moles of ethylene oxide, or a linear secondary alcohol condensed with a mixture of propylene and ethylene oxides, or a linear secondary alcohol condensed with a mixture of ethylene, propylene, and higher alkylene oxides.

The bisphenols which may be employed include 2,2- methylenebis(3,4,6-trichlorophenol), also known as hexachlorophene; 2,2 thiobis(4,4 dichlorophenol); 2,2- oxybis(1,5' dichlorophenyl 5 chlorophenol), also known as 2OH-2',4,4-trichlorodiphenyl oxide.

The following examples illustrate the practice of the instant invention.

EXAMPLES 1-4 Examples of concentrate compositions which can be employed with the instant invention are as follows:

EXAMPLE 1 Percent Water 70.0 Sodium salt of ethylene diamine tetraacetic acid 2.0 Monoethanolamine 2.5 Linear alkyl benzene sulfonic acid 8.0 Tall oil fatty acid 4.0 Propylene glycol 10.0 Nonionic B 2.0 Hexachlorophene 1.0

3,5 dimethyltetrahydro 1,3,5,2H thiadiazine-Z- thione 0.5

2,2 oxybis(l',5-dichlorophenyl-S-chlorophenol) 2.0 Di(triethanolamine)ethylenebis dithiocarbamate 2.0

EXAMPLE 3 Percent Water 58.0 Sodium salt of ethylene diamine tetraacetic acid 3.0 Sodium salt of sulfonated oleic acid 10.0 Tall oil fatty acid 5.0 Monoethanolamine 2.0 Propylene glycol 12.0 Nonionic B 8.0 2,2 thiobis (4,4 dichlorophenol) 1.0

3,5 dirnethyltetrahydro 1,3,5,2H thiadiazine-2- thione 1.0

EXAMPLE 4 Percent Water 58.2 Nitrilotriacetic acid 8.0 Linear alkyl benzene sulfonic acid 8.0 Tall oil fatty acid 5.0 Monoethanolamine 2.8 Propylene glycol 10.0 Nonionic A 5 .0 2,2'-oxybis(1,5'-dichlorophenyl-S-chlorophenol) 1.0

3,5 dimethyltetrahydro 1,3,5,2H thiadiazine-2- thione 2.0

In the above compositions:

Nonionic A defines a polyoxyalkylene polyol wherein a mixture of by weight 85 percent ethylene oxide and 15 percent propylene oxide is condensed with a mixture of normal fatty alcohols having from to 12 carbon atoms, the weight ratio of the ethylene oxide-propylene oxide mixture to alcohols being 4:1.

Nonionic B defines a polyoxyalkylene polyol wherein a mixture of "by weight 75 percent ethylene oxide and 25 percent propylene oxide is condensed with a mixture of normal fatty alcohols having from 12 to 18 carbon atoms, the weight ratio of ethylene oxide-propylene oxide mixture to alcohols being 4:1.

Nonionic C defines a polyoxyalkylene polyol wherein a mixture of by weight 60 percent ethylene oxide and 40 percent propylene oxide is condensed with a mixture of normal fatty alcohols having from 12 to 18 carbon atoms, the weight ratio of ethylene oxide-propylene oxide mixture to alcohols being 3:1.

In accordance with the instant invention, a 12-foot section of continuous bottle conveyor, driven by a /3 horsepower motor, is loaded with 50 water-filled bottles and the compositions of Examples 1-4 above diluted in a proportion by weight of 1:100 of the agent selected from the group consisting of bisphenols, thiadiazine thione, and dithiocarbamate to water. This dilute solution is then applied at a single application point at the end of the conveyor distal to the drive, thus simulating operating conditions of a section of an actual bottle conveyor. The relative efiiciency of the lubricant is determined by the force in pounds of gate pressure exerted by the stationary bottles on a spring balance at the end of the conveyor as the chain moves under the load. Compositions with poor lubricity will result in a higher gate pressure due to the force transmitted to the bottle column by friction of the chain passing under the bottle load. Generally, a lubricant yielding a gate pressure of greater than 12 pounds on the balance with the standard load will exhibit poor lubricity under actual use conditions.

The current load in watts of the drive motor is also proportional to the lubricity of the lubricant as related to friction between the bottle load and conveyor chain. The foam generating capacity of the test formula is determined by the height of the suds that build up between adjacent bottles. Lubricants giving a gate pressure of less than 12 pounds and an electrical load of less than 105 watts have been shown to perform satisfactorily in actual conveyor systems. The results of lubricity and foam generating capacity of the above compositions are indicated in Table I below.

TABLE I P.p.m. (CaCO Lubricity Foam hardness of water (pounds gate charac- It has been determined from field experience that if a specific type of organism survives on a conveyor it will persist for more than 30 minutes in the following type of laboratory test.

One milliliter aliquots of 24-hour broth cultures of bacteria are inoculated into milliliters of the 1:100 dilution of each concentrate composition described above with respect to the lubrication and foam tests. The organism-lubricant mixture is allowed to stand in a flask at room temperature for 30 minutes. One milliliter quantities are removed from the flask and plated on an appropriate media containing a neutralizing agent composed of lecithin and polyoxyethylene sorbitan monooleate. The plates are incubated at 28 C. to 37 C. for 48 hours and viable organisms determined. A formula with satisfactory antimicrobial activity would reduce the number of surviving organisms to less than 0.001 percent of the initial inoculum of 100x10 organisms per milliliter.

All of the compositions of the above examples are effective by this standard against Staphylococcus aureus, Pediacoccus cerevisiae, Leuconostoc mesenteroides, Bacillus mucoides, Escherichia coli, Pseudomonas aeruginosa, Sacchromycetes cerevisiae, Rhodotorula rubra, Penicillium italicum, and Aspergz'llus niger.

EXAMPLES 5-9 Additional examples of concentrate compositions which can be employed with the instant invention are as follows:

EXAMPLE 5 Percent Water 57.0 Nitrilotriacetic acid 3.0 Coconut oil fatty acid 10.0 Tall oil fatty acid 10.0

2,2-oxybis(1',5 dichlorophenyl 5 chlorophenol) 5.0 Polyoxyethylene (5) sorbitan monooleate 5.0 Monoethanolamine 10.0

3,5 dimethyltetrahydro 1,3,5,2H thiadiazine- 2-thione 1.0 Triethanolamine 4.2 Nonionic D 3.0

EXAMPLE 7 Percent Water 69.0 Sodium N-methyl-N-oleoyl taurate 5.0 Tallow fatty acid 10.0 2-ethyl hexoic acid 4.0 Monoethanolamine 5.8 2,2-thiobis(4,4-dichlorophenol) 2.0 Disodium ethylene dithiocarbamate 1.2 Nonionic E 3.0

EXAMPLE 8 Percent Water 62.1

N-hydroxyethylene diamine triacetic acid-trisodium salt 2 Sodium salt of dodecyl oxy dibenzene disulfonate 1 Tall oil fatty acid 16. Pelargonic acid 4 In the above compositions: Nonionic D defines a chlorinated alkyl phenol having 8 or 9 carbon atoms in the alkyl group and wherein a terminal hydroxyl group is replaced by Cl-.

Nonionic E defines an isobutylene capped alkyl phenol ethoxylate obtained from 10 to 16 moles of ethylene oxide per mole of alkyl phenol.

Nonionic F defines a polyoxyethylene adduct of a polyoxypropylene hydrophobic base having a molecular weight of about 1,750 wherein the oxyethylene content is about 40 weight percent of the molecule.

Nonionic G defines a polyoxyalkylene polyol wherein a 2:1 mixture by weight of propylene oxide and ethylene oxide is condensed with a mixture of normal fatty alcohols having from 12 to 18 carbon atoms, the weight ratio of propylene oxide-ethylene oxide mixture to alcohol being 3:1.

Each of the compositions of Examples -9 are diluted in a proportion by weight of 1:100 of the composition to water. This dilute solution is then applied to a conveyor for conveying bottles in a clean room for filling with filtered and/ or sterilized liquid whereby the presence of bacteria in the clean room is substantially eliminated.

The concentrate compositions of Examples 5-9 when diluted in proportions shown in Table II below and subjected to the lubricity and foam generating capacity tests described in Examples 14 give the results shown in Table II below.

TABLE II P.p.m. (C3003) Dilution, hardness of Lubricity Foam weight ratio water for (pounds gate eharacconcentrate Example dilution pressure) teristie to water 0 6. 0-5. 5 Moderate. 1:250 250 5.5-5. 0 Slight.--" 1:250 0 6.5-5. 5 High 1:200 250 5. 0-4. 5 Moderate" 1:200 0 7.0-6.0 d0 1:200 250 6. 5-5. 5 .do 1:200 0 6.0-5.0 High 1:200 250 5. 5-5. 0 Slight. 1:200 0 5. 5-4. 5 High 1:200 250 5. 04. 5 Moderate.. 1:200

It is to be understood that various changes and modifications may be made in'theforegoing without departing from the spirit of the invention and scope of the appended claims.

What is claimed is:

1. A concentrate which consists essentially of by weight about 30 to 70 percent water, about 2 to 8 percent sequestering agent, about 2 to 10 percent anionic surface active agent, about 4 to 15 percent fatty acid soap selected from the group consisting of fatty acid alkali metal soap and fatty acid alkanol amine soap, about 5 to 20 percent propylene glycol, about 2 to 10 percent nonionic surface active agent, and about 1 to 5 percent of a composition selected from the group consisting of bisphenols, thiadiazine thione, dithiocarbamate, and mixtures thereof.

2. The composition of claim 1 wherein said fatty acid soap is obtained by incorporating in said concentrate a fatty acid in an amount from about 2 to 30 percent by weight along with an agent selected from the group consisting of metal hydroxides and alkanolamines in amount suflicient to react with the fatty acid to produce the fatty acid soap.

3. A composition of matter consisting essentially of concentrate and water in a volumetric proportion of concentrate to water of about 1:50 to 1:500, wherein said concentrate consists essentially of by weight about 30 to 70 percent water, about 2 to 8 percent sequestering agent, about 2 to 10 percent anionic surface active agent, about 4 to 15 percent fatty acid soap selected from the group consisting of fatty acid alkali metal soap and fatty acid alkanol amine soap, about 5 to 20 percent propylene glycol, about 2 to 10 percent nonionic surface active agent, and about 1 to 5 percent of a composition selected from the group consisting of bisphenols, thiadiazine thione, dithiocarbamate, and mixtures thereof.

4. The composition of claim 3 wherein said fatty acid soap is obtained by incorporating in said concentrate a fatty acid in an amount from about 2 to 30 percent by weight along with an agent selected from the group consisting of metal hydroxides and alkanolamines in amount sufiicient to react with the fatty acid to produce the fatty acid soap.

References Cited UNITED STATES PATENTS 1,889,629 11/1932 Bohmer et a1. 5322 2,959,547 11/1960 Brillhart 25234X 3,310,489 3/1967 Davis 25249.3X 3,336,225 8/1967 Sayad et a1. 25249.3X

FOREIGN PATENTS 833,868 5/1960 Great Britain 25249.3

DANIEL E. WYMAN, Primary Examiner W. H. CANNON, Assistant Examiner US. Cl X.R. 

